Early Diagnosis of Oral Squamous Cell Carcinoma by Salivary microRNAs

Background: Oral squamous cell carcinoma (OSCC), the most common type of oral cancer, and represents more than 90% of malignancies of the oral cavity. Worldwide, each year about 275,000 are newly diagnosed. If detected at an early stage, OSCC has a survival rate of up to 80% compared to the detection in later stages (T-3-T-4) when a survival rate of 20 - 30% is present. Methods: Because OSCC presents these survival rates, there is an urgent need to introduce new non-invasive molecular biomarkers for the early detection of OSCC from saliva, which will contribute to an increased long term survival rate for these patients. Results: MicroRNAs represent small, non-coding RNAs that have important roles in biochemical mechanisms, carcinogenesis, cell proliferation, embryogenesis, and other mechanisms involved at the molecular level in the functioning of the human body. Conclusions: In the last decade, due to the fact that forensic genetics developed significantly, salivary microRNAs were increasingly studied as non-invasive molecular biomarkers which could aid in early diagnosis, monitoring, and prognosis of oral cancers. This review will present the most important salivary microRNAs which are involved in oral carcinogenesis, especially those which could be used as potential biomarkers in early detection, monitoring, and prognosis of oral cancers by non-invasive techniques.